Fan system



March '28, 1939; C L T 2,152,172"

FAN SYSTEM,

Filed Ma -23 mounon oEkowJm Iwvewfivr'. Amos 6, BA/eTLETT Patented Mar. 28, 1939 This invention relates to fanlsystems andfrea lates more particularly to afan systemfor." the ventilation of mines.

In a" mine having agiven areato supply with air, itlisdesirable to circulate a constant volume of air; I As shownby. ?.Coal'.Miner s Pocketbook published, by; the 'McGraw-Hill Book Company,

varie's'as thecube of the velocityland volumeso it is-always desirableitomaintain the velocity. and volume of air moved by theffan at the imini mum which will satisfy (the. requirements for ventilation.

of given'area varies with changes in barometric ture and pressure change, the change in volume is directly proportional to the change in absolute temperature according to Gay-Lussacs law, and is inversely proportional to the change in absolute pressure according to Mariottis; law. The changes in volume due to changes in pressure and temperature are substantial as shown by the fact that a drop in barometric pressure from 29.5 to 29.0"will cause a volume of 1,000,000 cubic feet of air to increase 17,250 cubic feet.- Likewise a rise in-temperature say from F. to 95 F. will cause a volume of 1,000,000 cubic feet of air to increase 37,400 cubic feet. In a shaft type mine of substantial depth, the above increases in volumewould be further increased due to the stack effect. I

According to this invention, there is provided for mines, a centrifugal fan with adjustable spin which approximates the movementofthe wheel so that the wheel has little efi'ect upon the air. This enables the volume of the fan to be varied while driven by aconstant speed motor. The inlet vanes are adjusted by a, velocity meter mounted in the passage leading to the fan, to' maintain a constant volume of, air through the passage. The cross-section of the passage isconstant so that the velocity meter responds accu-Z rately to changes in the volume of air passing it.

An object of the invention is to maintain a constant'volume of air through a mine of. given,

area. a

Another object of the invention is to provide for the ventilation of'a. mine, a centrifugal fan having adjustable spin inducing vanes in its inlet shafts' one f l the inlet of the ventilating ai pressureand temperature. When both temperastairways for the mines.

"8 as willjnow be explained. The velocity meter 8 which may be of the type manufactured by the p jrsiv'svsratr,. I Amos- '0. Bartlett,"BraintreefMasa, assignor to 'Y B. F. Sturtevantcompany, flydeParkyBostony arantula; zaq ess,"'sr aliqsirstiss :3 ClaimsJ' .(Cl. -50)" andto adjust the vanes tomaintain the desired r conditions within the mine. g

' Other objects of the invention .will beapparent from the following. description jtaken together' with thejdrawing. v a

The invention wili 'now be described with ref-- [erenc'e'to the drawing'lofwhich: thejpower required'to move mean. in a mine Fig. 2 is adiagrammatic view of a'fan with 1 controls according to} this invention, and

, Fig. 3 is a circuit schematic illustr ating'irelay Iswitchingfor reversing the vanecontrol. motor. The volume of air at agiven timeHin-a mine I.

Shaft mines] areiprovided with at .least two 15 and the other forfthe exhaust of the air. As shown by Fig. 1, it is usual'for the hoisting shaft 5 to serve also as the inlet for the ventilating air. The exhaust airv passage 6 may also contain I The fan house I over the shaft 6 contains the fan apparatus according to this invention, and mounted within the shaft 6. is the velocity meter 8 whichflresponds to I changesin the velocity of the air passing it to adjust the fans as'will now be described with reference to Fig. 2.

The, fan 9 is preferably similar to the one described inthe Patent No. 1,846,863 to H. F. Hagen,

with the exception that in the presentcase, a fan with asingle inlet is illustrated. Mounted within the inlet I 0 of the fan are the adjustable vanes 20, the functions, arrangement and adjustment of which are identical with those of said patent, and so will not be described, in detail here. It is believed to be sufficient to state that the cranks and links, etc., indicated generally by H are adjusted by the rotation of the gear l2, corresponding to the gear 48 of said patent. The gearyli. is in turn rotated bythe gear l3, mounted in the same shaft as the gear H which is rotated through the intermediary'of the chain or belt l5 from the motor l6. Rotation ofthe armature of themotor lli, in one direction adjusts the vanes 20 towards their full open position and rotation of the armature in the other direction adjusts 45 the vanes towards their closed position.

' The. operation and direction of rotation of the motor iii are controlled by the relays l1 and I8 which in turn are controlled by the velocity meter Illinois.TeStingLabOratorieS Inc. of Chicago, Illinois,-contains the vane "in contact with the moving air, the return spring 29,- the indicator 25 'and; contacts 26 and 21. At air velocities appreciably above that necessary to give the desired air volume, the indicator 2! is moved Iagainst the contact 21 to close a circuit including the solenoid winding of the relay l1 and the electric source 30 to cause the relay H to connect theileld and armature windings, of the motor [8 to the current source 30 to cause the motor IE to rotate in a direction to adjust the vanes of the fan towards closed position soastoreduce theaction-. of the fanupon theairl (The motor I Swill-rotate until the indicator leaves the contact 21.

At air velocities appreciably below that n'ecessary to give the desired air volume, the indicator moves against the contact 26 to energize there-' lay I! which then closes contactstosconnect,the armature and ileld of the motor ID111833196- tric source 30 but in reverse relation to each other tocause the motor to run in a reverse direction from that previously described to adjust the in-"j let vanes towards their open position. The motor will continue to run and adjus t thevanes until the circuit established by the indicator and restored to that'desi'red;

contact 26 is opened when the volume has Pressure and temperature responsiveinstrumerits could of course be used to control the air flow, but for practical considerations; an instru ment such as has been described, which will spond 'to condition: indicating change in volume,

is preferred.

Whereasone embodiment invention has been described for the purpose ;cf illustration, it

shouldbeunderstood'that' theii'nventi on is not to be limited to thefexact arrangement'described, as manydepartures' and modifications will suggest themselves to those skilleddn the art, after having had access to this disclosure.

*to changes in the volume of the air moving through said passage for adjusting said last mentionedmeans toimaintaina constantair volume moved through said passage and delivered by said L an. a

2. A fan system comprising in combination, a space to be ventilated, an exhaust fan, means iormingan air; enhaustpassage from said space :tosaidsfan, a;;.plurality of spin inducing vanes in the inlet to said tan, means for adjusting said vanes'ior varying the total volume of air extractedfrom said space" by said fan, and means reisponsive to changes in the volume in said-passage for, adjusting said last mentioned means for passage and exhausted by 'said fan,

3. A fan system comprising in combination, :a

space ,tofbe ventilated, means forming a iresh air passage-connecting with; said space, means for'ming an exhaust air passage'connecting yvithsaid space and theijatmospheraafan iri said exhaust air p ss ai' e' T tawing es air hrquehi' l' i sh :air" P e u l f d aw n ex s from said space andjfor discharging same, into the atmosphere, 9. pluralityloi spin inducing vanes in the inlet oi s'aid fan, means for adjusting said vanes and means responsive to changesfinthe volume" or air moving throughsaid exhaust air passage for adjusting said last mentioned 'rnea'ns, AMos cnnaR'I'ri 'rn',

nil 4 

